M. Panayotov*

Department of Animal science-Non-ruminant and other animals, Faculty of Agriculture, Trakia Univercity, 6000, Stara Zagora, Bulgaria (Manuscript received 5 May 2016; accepted for publication 11 August 2016)

Abstract. The subject of research are Bombyx mori L. cocoons, differentiated by the nature of their fluorescent radiation. In each fluorescent group 2 subgroups were formed prepared for unreeling through cooking at 80 and 90°C for 5 min. To account for the effect of fluorescence at various cooking temperature levels the basic technological traits signs of the silk filament and cocoons have been defined and analysed: total length of the silk filament (m), nonbroken filament length (m, %), raw silk pesentage (%) and reelability (%). It was found that fluorescence of cocoons has statistically significant (p≤0.01- 0.001) effect on the phenotypic manifestation of the technological traits. Within the two cooking temperature levels, the yellow fluorescent cocoons demonstrate higher values at 80 °C, and violet ones at 90°C. The better technological qualities and the lower cooking temperature in the yellow fluorescent cocoons give reason to believe that their use is economically more profitable for the silk reeling industry compared with violet fluorescent cocoons.